If, let's say, love and sexual desire were personified as Felix Unger and Oscar Madison — two hopelessly mismatched companions who cosmically completed each other — and begrudgingly had to share a tiny, slug-shaped apartment in your brain, which would it be? It's the insula and striatum duplex, silly — everyone knows that, or they do now thanks to researchers at Concordia University.

With the help of Swiss and American colleagues, psychology professor Jim Pfaus analyzed the results of 20 separate studies that monitored the brain activity of subjects gazing lustily at erotica or longingly at their significant others. After pooling all the data Pfaus and pals were able to play brain cartographers and determine that the progression from sexual desire to love occurs in the insula and striatum (the insula is folded deep within the temporal and frontal lobes while the striatum, a close neighbor, is located inside the forebrain).

Though linked, love and desire activate different parts of the striatum. Desire (the Oscar of our little extended metaphor) activates the part normally activated by things that are "inherently pleasurable," such as food, orgasms, or getting stoned, eating a whole bag of Funyuns, and sprinkling crumbs all over the couch just to mess with your OCD roommate. Love activates a part of the striatum that facilitates the process of conditioning, by which you learn that a pleasurable thing could also entail a reward. What this means is that sexual feelings can graduate from the Funyun-munching part of the striatum to the love-letter writing part.

That's cool, I guess, but the really interesting thing about this study is that the love part of the striatum is the same part associated with drug addiction. Pfaus explains that this makes perfect sense, of course, because, "Love is actually a habit that is formed from sexual desire as desire is rewarded. It works the same way in the brain as when people become addicted to drugs." There it is, folks — scientific proof that love is a habit-forming drug.